1. Field of the Invention
The present invention generally relates to hydrostatic bearings and stage apparatuses.
More specifically, the present invention relates to a hydrostatic bearing for sliding a slider on a sliding surface of an X-Y stage in a non-contact stage and a stage apparatus having the hydrostatic bearing.
2. Description of the Related Art
As a hydrostatic bearing for sliding a slider on a sliding surface of an X-Y stage in a non-contact state, techniques discussed in Japanese Laid-Open Patent Application Publication No. 2000-155186 have been suggested. The hydrostatic bearing discussed in this publication is provided at a lower end part of a slider of the X-Y stage.
The hydrostatic bearing receives a force toward a guide surface (sliding surface) of a base (structural body) due to the weight of the slider and a force in a direction where the bearing is separated from the guide surface due to application of pressure of air jetted to the guide surface of the base. While the forces from both sides in the vertical direction are applied to the hydrostatic bearing, the hydrostatic bearing moves along the guide surface in a non-contact manner.
In the hydrostatic bearing which floats above the guide surface due to jetting of the air, air is jetted toward particles situated in minute holes formed in the base or particles adhered on the surface of the base which may fly high and scatter in the vicinity of the apparatus.
Especially, in a case where a semiconductor substrate or the like is mounted on the base of the apparatus, scattering particles may be adhered on the semiconductor substrate.